Madrid (CNN) -- Spanish investigators are trying to figure out how a 5-month-old baby died on a baggage carousel at an airport in Alicante.

A spokeswoman for Spain's airport authority, AENA, said Thursday it's not clear how the baby ended up on the baggage belt for oversized luggage.

"The baby was on the baggage carousel, but could not have gotten there alone. Someone had to put the baby there. I don't know how the baby got there," said the airport spokeswoman, who by custom is not identified.

The infant's mother, an American woman, arrived at the airport late Wednesday on a flight from London's Gatwick airport with her baby and another young child, the spokeswoman said. The father, who is Canadian, was already there waiting at the Alicante airport, she added.

The baggage carousel is a flat, black rubber-type belt that moves only in one direction and is only activated when oversized bags are sent out on it for pickup. It's several feet long and passengers can stand on either side of it or at the receiving end, the spokeswoman said.

She said it was not immediately known if the infant was placed on the belt while it was stopped, or once it had started moving.

An unidentified security officer at the airport told CNN affiliate Atlas she didn't see the incident, but was told that "the mother apparently put (the baby) down on the conveyer belt when she went to reach for something. He was crushed by the conveyer belt and it killed him."

Airport medical personnel rushed to the scene but were unable to revive the infant, the spokeswoman said.

The Spanish Civil Guard said the baby's death appears to be an accident, but an investigation is under way.

After the baby was pronounced dead, the family had to wait for a judge to arrive, by Spanish law, so that the body could be moved. Civil Guards took statements from the parents at the airport, the airport spokeswoman said.

The baggage belt for oversized luggage -- which includes infant car seats and baby strollers -- is at one end of a large baggage claims hall at the Alicante airport, which handles 9 million passengers a year, the spokeswoman said.

The baggage carousel is in a secure area, and passengers go through it to claim their bags before they exit into the public arrivals hall. The father of the baby would not have had access to that area, the airport spokeswoman said.

Civil Guard and National Police spokesmen confirmed the nationalities of the mother and father as American and Canadian, respectively.

A U.S. Embassy spokesman in Madrid said that U.S. Consular officials are aware of the incident and are providing assistance.

A spokeswoman for the Canadian Embassy in Madrid said she could not comment and referred inquiries to the Canadian government's Department of Foreign Affairs in Ottawa.

Spanish newspaper El Pais reported the family had come to the Alicante area, on Spain's Mediterranean coast, for vacation, but authorities would not immediately confirm that.